This research was concerned with study of fracture strength of adhesive-lap-joined
composites. The tensile and peel tests were carried out with specimens manufactured hybrid stacked
composites, because the orientation of fiber and the interfacial fracture between the matrix and the
reinforcement had influence on failure strength of composites. Bamboo natural fiber layer was located
between polyester layers. The objective of this study was to evaluate the effect of fiber orientation on
failure strength properties of composites. The test results were presented by load-displacement graph
and finite element analysis. As a result, the load-directional orientation and the thinner thickness of
bamboo natural fiber layer have a good effect on peel and tensile-shear strength and failure shape of
adhesive-joined hybrid stacked composite.